Could Lieberman be McCain's most potent VP pick?

If a few votes had shifted eight years ago, Joseph Lieberman might now be the presumptive Democratic presidential nominee. Instead, the Connecticut senator, who won re-election in 2006 as an independent, is one of Republican John McCain's more potent political weapons, maybe even potent enough to make another run at vice president, this time as a Republican.

WASHINGTON — If a few votes had shifted eight years ago, Joseph Lieberman might now be the presumptive Democratic presidential nominee.

Instead, the Connecticut senator, who won re-election in 2006 as an independent, is one of Republican John McCain's more potent political weapons, maybe even potent enough to make another run at vice president, this time as a Republican.

"I'd love that," longtime friend and author Ben Wattenberg said.

Lieberman, the Democratic vice presidential nominee in 2000, chuckles at the idea, but doesn't rule it out.

"I am not a candidate. I am not interested in doing that," he told ABC News last month, though he wouldn't remove himself unequivocally.

McCain's campaign won't comment on its selection process.

This much is clear: Lieberman, who long ago broke with Democrats on the Iraq war but has a solid party-line voting record on nearly everything else, is playing such a key role in McCain's White House bid that a VP bid is possible.

Political analyst Stuart Rothenberg called Lieberman a "near perfect pick." Steve Clemons, a senior fellow at the New America Foundation, a centrist public-policy group, said such a move would be "game changing."

McCain could boast that he's the true change agent — a slap at presumptive Democratic nominee Barack Obama's "change" theme — by showing that he's willing to reach across the partisan divide for a ticket mate.

Lieberman offers other advantages, analysts said, such as:

Temperament. Lieberman's calm manner could be a soothing contrast to the fiery McCain.

Background. Lieberman's past was scrutinized thoroughly when he ran eight years ago. "You could say he's beyond reproach now," said Tobe Berkovitz, associate dean of the Boston University School of Communication.

Florida. Lieberman has long been a favorite of the state's elderly Jewish voters, and he plans to campaign in South Florida late this week for McCain. "Elections in Florida tend to be close, and he'd have some effect," said Lance deHaven-Smith, a professor of public administration and policy at Florida State University, in Tallahassee.

But there also are compelling reasons that Lieberman isn't likely to be on the ticket, notably that McCain already is having trouble convincing die-hard Republican conservatives that he's one of them.

"I suspect they would go crazy," said Timothy Walch, an Iowa-based author and vice presidential expert, "though I suspect in the end the conservatives would vote for McCain."

A Lieberman choice also could energize liberals. "This would probably make Democrats hate him even more," said Andrew Smith, the director of the University of New Hampshire Survey Research Center.

Absolutely, said Toby Chaudhuri, spokesman for Campaign for America's Future, a liberal group.

"Lieberman positioned himself to the right of Bush on pre-emptive war, corporate-defined trade policies and as a scold on morals and deficits," Chaudhuri said. "He seemed to find his voice only when assailing other Democrats."

Some analysts dismiss the idea that Lieberman would energize or deflate any voting bloc. "People vote for the top of the ticket," said Merle Black, a professor of politics and government at Emory University.

Then there's the age issue: Lieberman is 66, and McCain's 71. Cracks about the "geriatric" Republican ticket might enhance the appeal of Obama, who's a youthful-looking 47.

Even so, Lieberman is already a ubiquitous McCain champion. Last week he touted McCain's Iraq position at a Senate news conference, then defended McCain's ad tying Obama to celebrities Paris Hilton and Britney Spears. "The point of the ad is quite strong," Lieberman said. "Who's ready to lead America?"

Sunday on NBC, Lieberman scoffed at Obama's new position backing limited offshore oil drilling as part of a comprehensive energy package.

"Barack Obama says this weekend, 'maybe,' and 'and,' 'if,' 'but.' He did not endorse. He did not come out with a strong decision and say, 'I'm for offshore drilling,' " Lieberman said.

All this from a man who eight years ago was a disputed Supreme Court decision away from being Democrat Al Gore's vice president.

Lieberman has explained his support for McCain by noting that he's a true centrist, trying to heal the partisan divide that's long gridlocked Washington. He's talked that talk for years; in 1997, he and McCain received the Richard Nixon Center for Peace and Freedom award for their foreign policy efforts.

He and McCain have worked together often, on climate change, campaign finance, gun control and V-chip legislation.

If they team up now for the ultimate prize, the possibilities for mayhem seem boundless: A Democrat with a long history of backing abortion rights being cheered by a Republican convention throng next month? The Democratic chairman of the Senate Homeland Security and Governmental Affairs Committee working to promote Republican policies this fall? A Republican vice-presidential nominee who sits in on private Democratic Senate strategy sessions every Tuesday?